Socket member and resilient retainer for cutter bits



Oct. 9, 19

C. B. KREKELER SOCKET MEMBER AND RESILIENT RETAINER FOR CUTTER BITS Filed May 11; 1960 62400! 15? (ea am,

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United States Patent C) "ice 3,057,609 SOCKET MEMBER AND RESILIENT RETAINER FOR CUTTER BITS Claude B. Krekeler, Cincinnati, Ohio, assignor to The Cincinnati Mine Machinery Co., Cincinnati, Ohio, a corporation of Ohio Filed May 11, 1960, Ser. No. 28,376 20 Claims. (Cl. 262-33) This application has to do with the provision of socket members equipped with resilient retaining means and adapted to receive the shanks of cutter bits in mining machinery, the relationship of the parts being such that cutter bits may be installed in the socket members by a driving action and removed therefrom by a prying action with a suitable tool. Such structures very greatly facilitate the operation of changing bits in mining machinery and save many man-hours as compared with earlier structures in which the bit shanks are retained in the sockets by set screws. Further, the bits are held in a more positive fashion.

A structure of this general character is shown and described in the copending application of the same inventor, Serial No. 728,476, filed April 14, 1958, now Patent No. 2,965,365, and entitled Bits and Holding Means Therefor. In the structure of the said copending application there is a socket member having a longitudinal perforation to accept the shank of a cutter bit. A transverse hole is made in the socket member, intersecting the perforation, to receive the resilient retaining means. 'In essence, the resilient retaining means consists ofa rod peripherally embedded in a body of rubbery substance, usually but not necessarily circular in form. In the central portion of the resilient retaining means the resilient substance is cut away so as to expose the rod at least partially; and therelationship of the hole to the perforation is such that the rod in its central portion will extend at least part way into the perforation. When the resilient retaining means is placed in the hole, it will be evident that the rod is, as it were, floating in a mass of resilient substance and capable of movement in a plurality of directions. The shank of the cutter bit is so shaped that as it is driven into the perforation an end portion of it will deflect the rod, and thereafter the rod will move against a slanting surface formed on the cutter bit shank so as to urge the shank forwardly and downwardly in the perforation. The engagement is strong because the ends of the rod are embedded in masses of the resilient substance lying in portions of the hole extending beyond the shank-receiving perforation; and in the preferred form of the resilient retaining means the portion of the rod exposed in the perforation is also backed by resilient substance.

The fact that the resilient retaining means fills the hole in the socket member minimizes the entry of acidic mine Waters and cuttings or fines into the hole. The resilient retaining means will outlast many cutter bits; but when it is worn out it can readily be driven from the hole and a new resilient retaining means inserted.

Nevertheless in the cutting of some types of coal, the fines present a definite problem in connection with the resilient retaining means. The difiiculty arises primarily but not entirely from the fact that the fines tend to creep behind that portion of the body of resilient substance which backs the rod where it extends across the socket receiving perforation. The packing action :of the fines is enhanced by the fact that the cutter bit, the socket and the resilient retaining means are subjected to excessive vibrations during a cutting operation.

The accumulation of fines behind that portion of the resilient substance which backs the rod in the perforation tends to compress and distort the resilient substance 3,057,609 Patented Oct. 9, 1962 so as to force portions of it into the socket receiving perforation and to limit the range of movement of the rod. Furthermore, if fines pack behind the central portion of the resilient substance there is a tendency for them to creep into the rear portions of the end zones of the hole thus impairing resiliency there also. The col lection of fines behind the central portion of the body of resilient rubberysubstance sometimes reaches a point where this central portion will break or pull apart in the use of the resilient retaining means. Collection of fines between the shank of the cutter bit and end portions of the body ofresilient substance tends to move these portions outwardly in the hole, an action which is enhanced if the central portion of the resilient body is disrupted.

It is a primary object of the invention to provide means for Ininirnizingthe collection and packing of fines behind the operative portion of the resilient retaining means.

These and other objects of the invention which will be set forth hereinafter or will be apparent to one skilled in the art upon reading these specifications, are accomplished by that structure and arrangement of parts of which certain exemplary embodiments willnow'be described. Reference is made to thedrawings forming a part hereof, and wherein: X

' FIG. 1 is a vertical section of a socket member showing a cutting bit retained therein by a resilient retaining means, the figure showing one aspect of the invention of this application.

FIG. 2 is a horizontal sectional view of the same structure taken along the section line 2 2 of FIG. 1. FIG. 3 is a sectional view of a modified form of the invention.

FIG. 4 is asectional view of yet another modification.

FIG. 5 is a vertical sectional view corresponding to the section line 5-5 of FIG. 3.

FIG. 6.is a vertical sectional view tion of the invention.

FIG. 7 is a perspective view resilient retaining means.

FIG. 8 is-a perspective view of another form of resilient retaining means.

FIG. 9 is a perspective view. of a type of retaining means which omits the centralportion of the resilient rubbery body.

FIG. 10 is a longitudinal sectional view of a modified structure of resilient retaining means.

Referring first to FIG. 1, the index numeral 1 indicates a socket or block membervwhich may be considered as mounted on link elements 3 of the chain of a mining machine, or mounted on a rotary cutting head or the like. The socket member is provided with a perforation 4 to accept the shank 6 of a cutter bit. The cutter bit will have a head 7 provided with one or more abutment shoulders 8 or 9 to limit the extension of the shank into the'perforation and hence tolestablish gauge. .Cut-t-er bits of the type illustrated are normally forged structures having a cutting edge faced by an inset 10 of hard alloy as is Well known in the art. The bit Will be so shaped as to provide a slightly undercut abutment 11 in a position spaced from the top surface of the socket member. This last mentioned abutment is designed to be engaged by a suitable tool used to pry the cutter bit out of engagement with the socket member. Where the term cutter bit is used herein, those skilled in the will understand that cuitter bit holders are intended to be included.

The socket member 1 has a transverse hole 12 in which a resilient retaining means is positioned. This resilient retaining means, in its simplest form comprises a steel rod the central porton of which is exposed to engage the cutter bit shank as hereinafter described,

of another modificaof a preferred form of and bodies of resilient substance surrounding at least end portions of the rod. Normally, and preferably, the rod is embedded in a unitary body of the resilient substance which body is cut away at its central portion to expose the steel rod on one side only. The term central portion refers to that part of the resilient retaining means which lies partly within the perforation 4. It will be noted that the hole 12 is so positioned that the bared central portion of the rod will extend at least partially into the perforation where it can engage a notch 13 in the shank of the cutting bit. An end portion 14 of the rear edge of the bit shank is rounded or beveled in such a way that it will engage and deflect the steel rod to permit the shank to be driven into the perforation. The notch 13 in the bit shank has an operating surface 15 which is engaged by the rod and is so configured that the rod will urge the bit shank forwardly and downwardly in the socket member perforation.

Preferred forms of resilient retaining means are illustrated in FIGS. 7 to 10. The steel rod 16 is embedded in a body of rubbery resilient substance in such fashion that end portions 17a and 17b of the body completely surround end portions of the rod. A central portion 170 of the body is configured to expose the rod on one side as will be evident from the drawings. Or the central portion of the body may be omitted entirely as later described. The resilient substance is of rubbery character, and may consist of or comprise any of the natural or synthetic rubbers such as butadiene styrene, acrylonitrile and others. A preferred material is a chloroprene such as neoprene, which are resistant to mine waters of acidic character and also to oils.

The resilient retaining means is provided with a metallic cage having a back portion 18 of relatively narrow width, portions 19 extending across the ends of the resilient body, preferably front portions 20 embedded in the resilient body, and preferably also inturned portions 21 as shown to unite the structure. The back portion of the cage lies outside the periphery of the resilient body and, when located in a groove broached in the interior surface of the hole 12 will serve to maintain the resilient retaining means in position and against turning movement on its axis as will be evident from the drawmgs.

Since there is a tendency, as indicated above, for the end portions 17a and 17b of the resilient body to move outwardly by reason of the packing of fines, it is preferred to cover the ends of the body with metal discs 22 which lie inside end portions 19 of the cage and may be attached thereto (as in FIG. 8), or which constitute disc-like elements 22a formed integral with the cage as illustrated in FIG. 7. The disc-like elements also facilitate the removal and insertion of resilient retaining means in the socket member when it becomes necessary to change them.

Since the packing of fines occurs first behind the central portion 17c of the resilient body, one way in which the present invention may be practiced is illustrated in FIGS. 1 and 2, and constitutes the provision of a hole 23 behind the central portion of the resilient retaining means which will prevent fines creeping behind the central portion of the resilient body from packing. The hole 23 may be of various sizes and shapes and may be formed by drilling, broaching or otherwise. This is an effective way of accomplishing the primary object of the invention. Depending upon the cross sectional area of the hole 23 there will be some loss of support furnished by the socket member to the central portion of the resilient body; but it will be noted that the back portion 18 of the cage, being of stiff metal furnishes in itself a considerable measure of support. Although shown as of a diameter substantially equal to the diameter of the resilient retaining means, the hole can be made smaller so that the socket member itself continues to give some support to the central portion of the resilient body.

As shown in FIG. 3, another way of accomplishing the main object of the invention is to slot a rear portion of the socket member 1 inwardly adjacent the hole 12 as indicated at 24. This retains full support for the resilient retaining means in its central portion and preferably partly in the end zones 17a and 17b, where, however, the back portion 18 of the cage will also contribute support. The arrangement shown in FIG. 3 is effective because there is a tendency toward lateral migration of the fines behind the central portion 17c of the resilient body.

A combination of expedients is shown in FIG. 4 where the lateral faces of the socket member 1 are notched inwardly adjacent the hole 12 as at 25, and there is also provided a central perforation 23a.

As has been indicated, FIG. 5 may be regarded as a section taken along the section line 5-5 of FIG. 3; but it also indicates that the lower rear end of the shank may be cut away or chamfered as at 26 in such a way that the beveled portion terminates upwardly inside the diameter of the hole 12 so as to leave a passageway indicated at 27. A structure of this kind has been found reasonably effective in minimizing the packing of fines behind the central portion 17c of the resilient body. Investigation has shown that the fines tend to accumulate in by far the greater quantity at the lower edge of the portion 17c. Hence relief at this point tends either to minimize the packing of fines or to permit the fines to escape through the opening 27. It will be understood also that the provision of an opening such as 27 may be practiced in any of the structures shown in FIGS. 1 to 4 inclusive.

FIG. 6 illustrates yet another embodiment of the invention. In this instance an opening for minimizing the packing of fines has been provided by broaching back the lower rear inside surface of the perforation 4 so as to provide a passageway which in this figure is indicated by the numeral 28.

The force with which the rod 16 engages the cutter bit shank in the notch 13 can be controlled by proper selection and curing of the rubbery substance of which the resilient body is made. Generally a strong engagement is desirable. Generally also it is desirable to have a central portion backing that part of the rod 16 which extends across the perforation 4 in the socket member. Preferably the resilient body is molded about the rod 16 in the manufacture of the resilient retaining means; and the provision of an integral body consisting of end portions 17a and 17b and a central portion 170 facilitates this. However, in the practice of the invention it is possible to omit the central portion of the resilient body as shown in FIG. 9 where like parts have been given like index numerals. It has been found that fines will not pack behind a completely exposed rod 16 in the central portion of the structure providing there is a channel or orifice through which the fines can escape. This channel or orifice can be provided as i1lustrated at 27 in FIG. 5 or as illustrated at 28 in FIG. 6, or by the provision of a rearwardly extending hole 23 as illustrated in FIG. 2.

FIGURE 10 shows a modified structure, again with the central portion of the resilient body removed. In this embodiment the rod 30 is made integral with or welded to disc-shaped elements 31 and 32 at its ends. The end portions only of the rod are surrounded by masses 33 and 34 of the resilient substance. The structure of FIGURE 10 may be used with or without a cage such as described in connection with FIGURE 8. A portion of such a cage is indicated at 35; but since the disc-shaped elements 31 and 32 are attached to the rod, it will be evident that they must be free from the cage. Moreover the radius of the disc-shaped elements must 7 be shorter than the radius of the resilient masses 33 and 34 by somewhat more than the expected range of movement of the rod 30.

In a cutting operation the cutter bit, the socket member and the resilient retaining means are subjected to heavy vibrations in a plurality of directions. to have a relatively close fit of the shank 6 in the perforation 4. Even so, there will be wear on the parts including wear on the socket member not only within the perforation but also on its upper surface because of the action of the shoulders 8 and 9, and particularly the latter. In the drawings of this case there is illustrated an expedient of facing a portion of the upper surface of the socket member 1 with a hard alloy piece 29 against which the shoulder 9 bears. Wear which loosens the fit of the parts against each other facilitates the packing of fines; but the vibrations to which reference has been made tend to some extent to break up masses of packed fines so that they can escape through any of the escape openings hereinabove described.

Modifications may be made in the invention without departing from the spirit of it. The invention having been described in certain exemplary embodiments what is claimed as new and desired to be secured by Letters Patent is:

1. In combination a socket member having a perforation to receive the shank of a tool, the socket member having a hole extending transversely of said perforation and adapted to receive a resilient retaining means, a resilient retaining means comprising a rod, end portions of which at least are encased in resilient substance lying within portions of said hole extending beyond said perforation, and at least one opening formed in said socket member and extending from said hole to a surface of said socket member, said opening being so located with respect to said hole as to relieve and discharge an accumulation of fine cuttings which otherwise would collect between some portion of said resilient retaining means and an adjacent wall of said hole.

2. The structure claimed in claim 1 wherein said resilient retaining means has a central portion of resilient substance located substantially at one side of said rod and joining the portions of resilient substance encasing the end portions of said rod, and in which said opening is an opening located behind a portion at least of said resilient substance.

3. The structure claimed in claim 1 wherein said resilient retaining means has a central portion of resilient substance located substantially at one side of said rod and joining the portions of resilient substance encasing the end portions of said rod, and in which said opening is an opening located behind a portion at least of said resilient substance, and in which a cage member engages opposite side portions of said resilient substance and extends across the ends thereof, a portion of said cage extending across the opening and forming a support for the resilient substance thereat.

4. The structure claimed in claim 2 wherein the opening to alleviate the packing of cuttings has a slot-like configuration extending inwardly from at least one side of said socket member.

5. The structure claimed in claim 2 wherein 'the opening to alleviate the packing of cuttings has a slot-like configuration extending inwardly from at least one side of said socket member, the resilient material being engaged in a cage member having parts lying along opposite sides thereof and across the ends of the resilient material, a portion of said cage member extending across said slot and furnishing support for said resilient material thereat.

6. The structure claimed in claim 4 having additionally an opening in said socket member extending at right angles to said hole and located substantially at the central portion of said hole.

7. The structure claimed in claim 4 having additionally an opening in said socket member extending at right angles to said hole and located substantially at the cen- It is desirable 6 tral portion of said hole, said resilient material being engaged in a cage member having parts lying along opposite sides and across the ends of said resilient material, a portion of said cage extending across said slot and said opening and forming a support for said resilient material.

8. In combination a socket member having a perforation to receive the shank of a tool, said socket member having a transverse hole intersecting said perforation, a resilient retaining means in said hole comprising a rod, end portions at least of which are encased in resilient substance lying within portions of said hole off side said performation, and a tool having a shank engaged in said perforation with said rod engaging in a notch in said shank, the said structure being characterized by an opening leading from a point Where fines may be expected to collect between said resilient substance and the walls of said hole to a point at the surface of said socket member.

9. The structure claimed in claim 8 in which said opening is formed by a chamfering of said shank.

10. The structure claimed in claim 8 wherein said opening is formed by a recess in a wall of said socket member.

11. The structure claimed in claim 8 wherein said opening is a second hole formed through a wall of said socket member and intersecting said first mentioned hole.

12. The structure claimed in claim 8 wherein said opening is a slot formed in a lateral portion of said socket member and connecting with said hole.

13. The structure claimed in claim 8 wherein opposite lateral portions of said socket member are slotted inwardly to connect with said hole and in which there is a second hole at right angles to said first mentioned hole, connecting therewith at the central portion of said socket member and extending to a surface of said socket member.

14. In combination a socket member having a perforation to receive the shank of a tool, and having a hole extending transversely of said perforation and intersecting it, a resilient retaining means located in said hole, said resilient retaining means comprising a rod, end portions only of which are surrounded by resilient substance lying within portions of said hole off-side said perforation, a tool having a shank engaged in said perforation with said rod engaged in a notch in said shank, said combination being so configured that there is an opening from a point outside said socket member to the central portion of said hole.

15. A resilient retainig means comprising a rod, masses of resilient substance encasing end portions of said rod, a cage member having portions lying upon opposite sides of said masses of resilient substance and across the outer ends thereof, one such portion being continuous from end to end of the resilient retaining means, and disc shaped elements lying at the outer ends of said masses of resilient substance.

16. The structure claimedin claim 15 in which said disc shaped elements are integral with the remainder of said cage.

17. The structure claimed in claim 15 including a mass of resilient substance lying between said first mentioned masses of resilient substance, confined substantially to one side of said rod, and integral with said first mentioned masses.

18. The structure claimed in claim 17 wherein said disc-shaped elements are integral with said cage.

19. A resilient means for retaining the shank of a cutter bit device in a socket member having a perforation to receive the shank, and a hole transverse and intersecting the perforation to accept the said resilient retaining means, the said resilient retaining means comprising a rod a central portion of which is exposed for contact with the shank and deflection thereby in a direction transverse the axis of the rod, masses of resilient substance encasing at least end portions of said rod and forming therewith a structure which may be placed in said hole, said masses of resilient substance serving when the structure is soplaced to mount said rod resiliently for said deflection, and disc-like members attached to the ends of said rod and lying beyond the ends of said masses of resilient substance, said disc-like members being of lesser transverse dimensions than said masses and serving to inhibit endwise distortion of said masses when said rod is deflected.

20. The structure of claim 19 icluding a cage comprising a part extending longitudinally of said resilient retaining means, other parts lying across said disc-like members, and parts extending inwardly along said masses of resilient substance and lying opposite said longitudinally extending part.

References Cited in the file of this patent UNITED STATES PATENTS 559,812 Ross May 12, 1896 1,823,168 Read Sept. 15, 1931 1,861,053 Dykstra May 31, 1932 2,155,526 Bowman Apr. 25, 1939 2,289,464 Simmons July 14, 1942 2,322,929 Fulke June 29, 1943 2,434,256 Bowman Jan. 13, 1948 

